How well are aerosol–cloud interactions represented in climate models? – Part 1: Understanding the sulfate aerosol production from the 2014–15 Holuhraun eruption

• Main Authors: Jordan, G, Malavelle, F, Chen, Y, Peace, A, Duncan, E, Partridge, DG, Kim, P, Watson-Parris, D, Takemura, T, Neubauer, D, Myhre, G, Skeie, R, Laakso, A, Haywood, J
• Format: Article in Journal/Newspaper
• Language: English
• Published: European Geosciences Union / Copernicus Publications 2024
• Subjects: Holuhraun; Iceland
• Online Access: http://hdl.handle.net/10871/136218; https://doi.org/10.5194/acp-24-1939-2024

This is the final version. Available on open access from the European Geosciences Union via the DOI in this record Data availability: The IASI SO2 retrieval dataset is available on the CEDA Archive at https://catalogue.ceda.ac.uk/uuid/d40bf62899014582a72d24154a94d8e2 (Carboni et al., 2019b). The EMEP network surface SO2 and mass concentrations are available through the EBAS database (https://ebas.nilu.no/data-access/, Norwegian Institute for Air Research (NILU), 2023). All model data, including trajectory output, used in this study are available on Zenodo at https://doi.org/10.5281/zenodo.10160538 (Jordan, 2023). Code availability: Code is available from the corresponding author on reasonable request. For over 6 months, the 2014-2015 effusive eruption at Holuhraun, Iceland, injected considerable amounts of sulfur dioxide (SO2) into the lower troposphere with a daily rate of up to one-third of the global emission rate, causing extensive air pollution across Europe. The large injection of SO2, which oxidises to form sulfate aerosol (SO42-), provides a natural experiment offering an ideal opportunity to scrutinise state-of-the-art general circulation models' (GCMs) representation of aerosol-cloud interactions (ACIs). Here we present Part 1 of a two-part model inter-comparison using the Holuhraun eruption as a framework to analyse ACIs. We use SO2 retrievals from the Infrared Atmospheric Sounding Interferometer (IASI) instrument and ground-based measurements of SO2 and SO42- mass concentrations across Europe, in conjunction with a trajectory analysis using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, to assess the spatial and chemical evolution of the volcanic plume as simulated by five GCMs and a chemical transport model (CTM). IASI retrievals of plume altitude and SO2 column load reveal that the volcanic perturbation is largely contained within the lower troposphere. Compared to the satellite observations, the models capture the spatial evolution and vertical variability of ...